Electrical contact terminal having closed entry receptacle and connector

ABSTRACT

Stamped and formed electrical contact terminal comprises a crimp portion of U-shaped cross section and a contact portion in the form of a tongue extending from the crimp portion. The tongue is reversely bent and has a locking section extending into the crimp portion. Upon crimping of the crimp portion onto a wire, the locking section is locked to the crimped connection to provide a closed entry receptacle. Connector housing for the disclosed terminal has a cavity such that the terminal need not be preferentially oriented during insertion.

United States Patent [191 Travis ELECTRICAL CONTACT TERMINAL HAVING CLOSED ENTRY RECEPTACLE AND CONNECTOR [75] Inventor: Allen Edwin Travis, Harrisburg, Pa.

[73] Assignee: AMP Incorporated, Harrisburg, Pa.

[22] Filed: Nov. 26, 1971 [21] Appl. No.: 202,325

[52] US. Cl..... 339/223 R, 339/192 RS, 339/217 S,

339/256 R [51] Int. Cl H0lr 15/12 [58] Field of Search 339/217 R, 217 S,

339/223, 256, 258, 276 R, 276 T, 278 T, 252 P, 192 R, 192 RS, 176 M, 176 F, 176 MP [56] References Cited UNITED STATES PATENTS 1,067,702 7/1913 Wiegand 339/223 R 3,456,235 7/1969 Kennedy 339/258 3,654,592 4/1972 Primorac 339/176 MP 1 Dec.4, 1973 Fulton 339/223 R Krehbiel 339/217 S Primary ExaminerMarvin A. Champion Assistant Examiner-Robert A. Hafer Att0rney--William J. Keating et al., Gerald K. Kita,

John R. Flanagan and Allan B. Osborne 5? ABSTRACT Stamped and formed electrical contact terminal comprises a crimp portion of U-shaped cross section and a contact portion in the form of a tongue extending from the crimp portion. The tongue is reversely bent and has a locking section extending into the crimp portion. Upon crimping of the crimp portion onto a wire, the locking section is locked to the crimped connection to provide a closed entry receptacle. Connector housing for the disclosed terminal has a cavity such that the terminal need not be preferentially oriented during insertion.

1 Claim, 11 Drawing Figures ELECTRICAL CONTACT TERMINAL HAVING CLOSED ENTRY RECEPTACLE AND CONNECTOR BACKGROUND OF THE DISCLOSURE This invention is directed to the achievement of an improved closed entry electrical contact terminal and a connector housing adpated to receive the terminal. The disclosed embodiment of the invention is particularly intended for use with a hermetically sealed pin header of the type used in compressor housings to permit electrical connections to be made between the electrical apparatus contained in the housing and external circuitry. It will be apparent to those skilled in the art that other uses can be made of the principles of the invention.

The term closed entry receptacle as used herein refers to an electrical contact terminal having a receptacle portion which adapted to receive a contact pin or the like and which is uninterrupted around its periphery. Many stamped and formed sheet metal terminals or receptacles have an axially extending open seam so that if an oversized pin or other device is inserted into the receptacle, it may be overstressed and irreparably damaged to the extent that it will be incapable of establishing electrical contact with a subsequently inserted pin member. A closed entry receptacle on the other hand, cannot be so damaged unless grossly excessive force is applied which is sufficient to completely destroy the terminal. Under many circumstances, closed entry receptacle terminals are required for reliability purposes even though they usually are more expensive than stamped and formed terminals which do not have this feature of a closed entry.

The invention is also directed at the achievement of an improved stamped and formed electrical contact terminal having an improved retention lance means for retaining the terminal in the cavity of the connector housing. Retention lances as commonly provided on contact terminals are frequently a point of weakness in that they are subject to dam age by overstressing or they may be improperly set during the stamping and forming process (i.e. they will not extend at the required oblique angle from the terminal to retain the terminal in the housing terminal). Retention lances in accordance with the invention are virtually incapable of being damaged by overstressing and need not be set in the usual sense during manufacture of the terminal.

Finally the invention is directed to the achievement -of improved connector housing having a contactreceiving cavity which is incapable of accepting a terminal in an improper orientation and which further can be manufactured by a simple and inexpensive injection molding process.

It is accordingly an object of the invention to provide an improved electrical contact terminal having a closed entry receptacle. A further object is to provide a stamped and formed contact terminal having an improved receptacle portion. A further object is to provide a stamped and formed terminal having an improved retention lance. A still further object is to provide an electrical contact terminal having an improved retention lance in combination with a closed entry receptacle which is adapted to receive a contact pin or the like. A still further object is to provide an improved connector housing for receiving a contact terminal in accordance with the invention.

These and other objects of the invention are achieved in a preferred embodiment thereof which is briefly described in the foregoing abstract, which is described in detail below, and which is shown in the accompanying drawing in which:-

FIG. 1 is a perspective view of an uncrimped terminal in accordance with the invention.

FIG. 2 is a sectional side view of the terminal of FIG. 1

minal crimped onto the end of a wire.

FIGS. 4 and 5 are views taken along the lines 4-4 and 55 of FIGS. 2 and 3 respectively.

FIG. 6 is a perspective view of a section of strip metal illustrating steps in the stamping and forming of electrical contact terminals in accordance with the invention.

FIG. 7 is a fragmentary semi-diagramatic sectional view taken through the wall of a compressor housing illustrating the use of a connector in accordance with the invention.

FIG. 8 is a sectional perspective view of a preferred form of connector housing in accordance with the invention which is adapted to receive terminals of the type shown in FIGS. l-3.

FIG. 9 is a plan view of the receptacle portion of a contact terminal in accordance with the invention with a pin of proper size inserted into the receptacle.

FIG. 10 is a view similar to FIG. 9 but with an oversized pin inserted into the receptacle.

FIG. 11 is a sectional plan view of a connector in accordance with the invention.

As shown in FIGS. 1 and 11, an electrical contact terminal 2 in accordance with the invention is adapted to be crimped onto the end of a wire 4 and inserted into a housing 6 having three contact receiving cavities 8 extending therethrough. Openings 10 (FIG. 8) are provided in one wall 58 of the housing and communicate with the cavities 8, these openings being located such that they are in alignment with the receptacle portions of the terminals. The connector housing, with the terminals contained therein, is intended to be assembled to the electrical contact pins 12 of a hermetic header 14 mounted in the wall 16 of a compressor housing as shown in FIG. 7. The connector 6 is intended for use in the interior of the sealed housing to provide the electrical connections from the external circuitry to the electrical components contained in the compressor. A high degree of reliability is required of contact'terminals and connectors used in the interiors of compressors for making these connections because of the inassessability of the connector and the expense of effecting repairs in the event that the connector or one of its terminals should fail. In fact, it is frequently more economic to discard the entire compressor than to attempt to repair a malfunctioning component contained inside the sealed compressor.

The contact terminal 2 may be of any suitable conductive metal. If the terminal is intended for high amperage service, alloy ASTM CA 194 (97.5% Cu 5 %..F, .Q-.Q3i' 1 nd.Q- .25% Zn) nj prite ban! @0- dition is well suited by reason of its superior conductivity. The terminal comprises a receptacle portion generally indicated at 18, a first ferrule forming portion 20 of U-shaped cross-section which is adapted to be crimped onto the conducting core of the wire 4, and a second ferrule forming portion 22 which is adapted to be crimped onto the insulation of the wire as shown in FIG. 3 is a view similar to FIG. 2 but showing the ter- FIG. 3. The ferrule forming portion 22 comprises a bight 24 having sidewalls 26 extending upwardly therefrom which are adapted to be curled onto the wire insulation. The ferrule forming portion 20 similarly has a bight 28 which is relatively flat and which is co-planar with the bight 24. Sidewalls 30 extend upwardly on each side of the bight and are adapted to be crimped onto the conducting core of the wire in the known manner by being curled inwardly towards each other and downwardly towards the bight as shown in FIG. 5.

The contact receptacle portion 18 is generally triangular comprising a first section in the form of a tongue 32 extending forwardly from the bight 28 and laterally beyond the sidewalls 30. This tongue is reversely bent at 34 to define a second section which extends obliquely upwardly at 36 and which is again bent downwardly at 38 to define the third section 39 of the triangular receptacle. A locking section 40 of reduced width extends rearwardly from the side 39 and is centrally disposed between the sidewalls 30 of the ferrule forming portion 20 of the terminal. This locking section is joined to the side 39 by a transition section 42 that extends angularly with respect to both the side 39 and the locking section 40. As will be explained below, this transistion section permits accomodation of an oversized contact pin in the receptacle without damage to the contact receptacle. Shallow grooves or serrations 44, 45 may be provided on the upwardly facing surfaces as viewed in FIG. 2 of the locking section and the bight 28 to improve the reliability of the crimped connection.

Retention lances 46 are provided on each side of the first section or first side 32 of the receptacle portion of the terminal. These lances extend generally downwardly from the curve of the bend 34 and rearwardly towards the first crimp portion 20. Retention lance stops 47 project downwardly from the ends of the one side 39 of the receptacle and are opposed to the ends of the retention lances so that these lances cannot be overstressed by being flexed upwardly. In the absence of the stops 47, it would be possible to bend the lance upwardly to the extent that they would take a permanent set in their bent positions. It will be apparent from a comparision of FIGS. 2 and 3 that the angle between the lances 46 and the first section 32 of the receptacle is greater in the crimped terminal (FIG. 3) than in the uncrimped terminal (FIG. 2). The reason for this difference will be explained below with reference to FIG. 6, however, it should be pointed out at this stage that the lesser angle of the retention lance prior to crimping is distinct advantage for the reason that terminals in accordance with the invention are manufactured in the form of a continuous strip and are stored and transported on reels. There is, therefore, a tendency for the terminals of one row on the reel to become interlocked with the terminals of the next adjacent row, a condition which interferes with unreeling of the terminal strip when it is fed to the terminal crimping apparatus. The lesser angle of the lances in the uncrimped terminal reduces the tendency towards interlocking of the terminals on the reel.

Terminals in accordance with the invention can be applied to the ends of the wires with known types of automatic or semi-automatic crimping machines having means for feeding the terminal strips to the crimping station, for crimping the leading terminal of the strip onto the wire, and for simultaneously severing the terminal from the strip. When the crimping operation is carried out, sidewalls 30, 26 are bent inwardly and downwardly into engagement with the wire. Upon crimping of the sidewalls 30, the wire is compressed against the web 28 and the sidewalls and portions of the wire (depending upon the wire size) are pressed against the locking section or locking tongue 40. The sections 36 and 39 of the receptacle are thus swung through a slight clockwise are as viewed in FIG. 2 upon crimping and the lances are swung outwardly through a clockwise arc so that they assume the positions of FIG. 3. The lances are thus finally positioned at the time of crimping.

FIG. 6 shows the several stages through which the strip metal passes during formation of a strip of terminals in accordance with the invention. The reference numerals used to denote the blank and the partially formed terminals are the same as the numerals used to denote the parts of the terminal but are differentiated by prime marks. It will thus be apparent if the strip of FIG. 6 is examined from right to left that the blank is first formed and recesses 43 are formed on each side of the locking section 40 to define the stop members 47. The serrations 44 and 45 are then formed on the surfaces of the locking section 40 and the ferrule forming section 22'. Subsequently, the stop members 47 are bent upwardly and the locking section 44' is bent downwardly and rearwardly. Finally, the bend 34' is imparted to the blank in several stages until the locking section is disposed between the sidewalls 30' of the ferrule forming section 20.

During this bending operation, and particularly during the final stages of the bending operation, the locking section will be moved downwardly against the upper surface of the web 28, however, and because of the spring back, that is the limited elasticity that remains in metal after it has been plastically formed, the receptacle will open up slightly and the locking section will assume the position of FIG. 2 in the finished strip. Also, during the bending operation, the lances 46' will be swung downwardly as a result of the bending step. As previously noted, these lances will not assume their final position in the strip prior to crimping but will spring back to the positions of FIG. 2 after the strip leaves the forming die and will then be returned to their normal positions upon crimping as shown in FIG. 3.

This method of forming the lances 46 is distinctly advantageous in that they are not individually set; in other words it is not necessary to plastically deform each lance at its inner end in order to impart to it the desired angular relationship to the terminal. A lance setting operation, as ordinarily carried out in the terminal manufacturing art, requires that the metal at the inner end of the lance be plastically defonned and this results in a work-hardening of the metal at the inner end of the lance and a corresponding reduction in its elasticity. A stronger lance is thus achieved in accordance with the manufacturing steps shown in FIG. 6.

The housing 6 is of relatively simple construction and may be manufactured of a suitable thermo-plastic material such as nylon by an injection molding process. The individual cavities 8 have a rectangular crosssection which is dimensioned to receive the receptacle portion 18 of a terminal between sidewalls 59. The lefthand end of each cavity as viewed in the drawing is provided with inwardly extending grooves or recesses 64 on each sidewall adjacent to the housing topwall 56 and the lower wall 58. These grooves define leftwardly facing shoulders 66 in each sidewall 59 against which the trailing edges of the lances 46 of an inserted contact terminal are adapted to lodge. Since lances are provided on both of the sidewalls 59, the terminals can be inserted with its lances against either one of the sidewalls 59. Because of the rectangular cross-section of the cavity 8 and the dimensions of the receptacle portion 18 of the terminal, an individual terminal cannot be improperly inserted with its lances against the top wall or the bottom wall. Leftward movement of the individual terminals through the cavities is prevented by stop members which are integral with, and which extend from, the top and bottom wall of the cavity. It will be apparent from an inspection of FIG. 8 that the housing 6 can be manufactured with a straight action mold having interengaging core pins for forming the groove 64, the shoulders 66, and the stops 60, 62. The openings may then be provided in the finished molding by a simple punching operation. Parts which can be manufactured with such a straight action mold (i.e., which do not require core pins extending transversely of the direction of which the mold opens and closes) can be manufactured much more cheaply than parts which require more complex molding procedures.

A salient and overall advantage of the invention, as pointed out above, is that a closed entry receptacle is achieved in a stamped and formed contact terminal by virtue of the fact that the locking section 40 is joined to the web 28 when the terminal is crimped onto the wire. As also explained previously, the retention lances 46 of the disclosed embodiment have excellent strength characteristics by virtue of the fact that they are not set in the usual sense during the stamping and forming operation but assume their final position by virtue of the band 34 which is imparted to the receptacle portion of the terminal. Additionally, these lances do not extend at an extreme angle when the terminal is in its uncrimped position thereby minimizing tangling in reeled terminal strip. The stops 47 prevent any overstressing of the lances after the terminal has been crimped onto a wire so that the possibility of damage to the lances after crimping and prior to insertion into the connector housing is thereby avoided. An additional significant advantage of the invention results from the fact that the strip end of the wire 4 is maintained in intimate contact with both the web and sidewalls of the ferrule portion 20 and with the locking portion 40 of the receptacle 18. As a result of this fact, two separate current paths are provided from the end of the wire to the receptacle section. This electrical advantage is of particular significance in connectors of the type shown which are intended for compressor headers since terminals of this type are frequently required to carry 35 to 40 amperes in normal service and must be capable of accomodating surge currents of up to or more amperes for a short time period when the compressor is started.

When a terminal in accordance with the invention is assembled to a properly sized pin as shown in FIG. 10, the pin will contact the receptacle as shown in FIG. 9 and there will be little distortion of the receptacle. If a greatly oversized pin is inserted into the receptacle as shown in FIG. 10, it can be accomodated by straightening or partial straightening of the transition section 42 between the side 39 of the receptacle and the locking tongue 40. As shown in FIG. 3, this transition section 42 extends substantially normally of the side 32 but as shown in FIG. 10, if an oversized pin 12 is inserted, the transition section 42 will be straightened so that it extends obliquely with respect to the side 32 of the receptacle.

What is. claimed is:

1. A stamped and formed electrical contact terminal which is adapted to be crimped onto a wire, said terminal comprising:

a ferrule portion comprising a bight and sidewalls, said sidewalls being adapted to be curled inwardly towards each other and crimped onto said wire,

a contact portion comprising an extension of said bight, said contact portion having a reverse bend, and a reversely extending portion extending from said reverse bend, and having an integral locking section on its end, said locking section being between said sidewalls,

said contact portion having retention lances, one of said lances being on each side of an axis of said terminal which extends medially in the direction of said bight, said lances being integral with said contact section at said reverse bend and extending generally tangentially from said reverse bend rearwardly towards said ferrule portion and laterally away from said bight whereby,

upon placement of a wire between said sidewalls and crimping of said sidewalls onto said wire, said locking section is clamped tightly against said bight and said reversely extending portion is circumferentially stressed, and said lances are moved outwardly from said bight and set so that they extend at a predetermined angle with respect to said bight. 

1. A stamped and formed electrical contact terminal which is adapted to be crimped onto a wire, said terminal comprising: a ferrule portion comprising a bight and sidewalls, said sidewalls being adapted to be curled inwardly towards each other and crimped onto said wire, a contact portion comprising an extension of said bight, said contact portion having a reverse bend, and a reversely extending portion extending from said reverse bend, and having an integral locking section on its end, said locking section being between said sidewalls, said contact portion having retention lances, one of said lances being on each side of an axis of said terminal which extends medially in the direction of said bight, said lances being integral with said contact section at said reverse bend and extending generally tangentially from said reverse bend rearwardly towards said ferrule portion and laterally away from said bight whereby, upon placement of a wire between said sIdewalls and crimping of said sidewalls onto said wire, said locking section is clamped tightly against said bight and said reversely extending portion is circumferentially stressed, and said lances are moved outwardly from said bight and set so that they extend at a predetermined angle with respect to said bight. 